Virtual Server 2005 Takes Flight

by Alex Woodie

Windows shops looking to get a handle on X86 server sprawl may want to check out the new virtualization technology Microsoft made available this week. Virtual Server 2005, which is based on technology acquired in Microsoft's purchase of Connectix, in 2003, allows users to run Windows, Linux, and other X86 operating systems on the same box, and provides benefits in the areas of server consolidation, software testing, support for legacy applications, and disaster recovery.

Sophisticated virtualization technology that allows a single symmetric multiprocessor (SMP) server to run multiple instances of an operating system has been available on high-end mainframe, Unix, and OS/400 platforms for quite some time. While VMware (now owned by EMC) introduced virtualization technology for X86-based servers three years ago, most Windows shops still use separate servers for each critical application, which has contributed to the problem of X86 server sprawl.

Microsoft's answer to the problem of server sprawl is Virtual Server 2005, a multithreaded application that runs as a system service on Windows Server 2003. Virtual Server allows users to carve out their SMP servers into a host box running multiple operating instances, or what Microsoft calls virtual machines. Each virtual machine thinks it's in full control of the computer and is unaware of other operating instances running on the same system.

Virtual Server 2005 supports all "major" X86 server operating systems as guest operating systems in its virtual machines, including Windows NT 4.0, Windows 2000, Novell Netware, IBM OS/2, and, perhaps most important, Linux. While users will be able to run Linux operating systems on the same Intel or Advanced Micro Devices X86-based processor, Microsoft's operating systems will be "tuned" to run the most efficiently on Virtual Server 2005, the company says.

The number of virtual machines that can be squeezed out of a given server with Virtual Server 2005 depends on a number of factors, Microsoft says, including the number of processors, the amount of memory, and system bus throughput. Virtual Server 2005 scales down, allowing a single physical processor to be carved into multiple virtual machines; however, the product does not at this time scale up, and a single virtual machine can't span multiple physical processors, confirmed Eric Berg, Windows server group product manager.

Administrators manage and control Virtual Server through the Virtual Machine Monitor (VMM) interface. The VMM provides both weighted and fine-grain control mechanisms for determining how much of a given processor each virtual machine can consume. Administrators can also allocate how much memory each virtual machine is allotted, for both NUMA and non-NUMA systems. While processor capacity can be changed on the fly, virtual machines must be stopped before memory allocation is changed.

Virtual Server 2005 can run on SMP servers with up to 32 processors and use up to 64 GB host RAM, with up to 3.6 GB per virtual machine. The software can also present up to four emulated IDE hard disks or optical drives, providing up to 128 GB per IDE channel; it supports up to four virtual SCSI busses; and it supports up to four virtual Ethernet networks. The software is available in two versions: a standard edition, which supports symmetric multiprocessor (SMP) servers with up to four processors and costs $499, and an enterprise edition, which works on up to 32-way SMP servers and costs $999. Besides the number of processors supported, there is no difference between the two editions.

PUTTING VIRTUAL SERVER TO USE

Microsoft sees several benefits to using Virtual Server, including consolidation of X86 servers, rehosting of legacy applications (specifically those written for NT 4.0), disaster recovery, and streamlining software testing and deployment.

Virtual Server can help users more easily test distributed applications from third parties that typically require multiple servers to test, as well as software from Microsoft. As we have seen with the release of Windows XP Service Pack 2, it is critical that Windows shops test Redmond's patches before putting them into production. While Service Pack 2 is targeted at the desktop, that release represents a watershed moment for the way that Microsoft intends to push security patches, service packs, updates, and sundry enhancements out to its customers, both Windows server and desktop users. With Windows Server 2003 Service Pack 2 (with the XP SP2 security enhancements) just around the corner, now is an excellent time to get your testing processes in place, and Virtual Server 2005, or other virtualization technologies, for that matter, could be a valuable piece of that solution.

Microsoft also sees Virtual Server being used to cut costs in disaster recovery scenarios, because users will no longer need separate servers to provide backup for each primary servers; backups of multiple applications running across a number of physical servers can be directed toward a single server, with a virtual machine for each application. The software also supports two-node clustering, Microsoft says.

Many Windows shops are still running older NT 4.0-based applications and have been reluctant to upgrade to newer versions of Windows because it would an entail an extensive redevelopment effort to get their older applications running smoothly on a newer platform. With Virtual Server 2005, organizations can run their homegrown NT 4.0 applications unchanged in its own partition on a Windows Server 2003 box.

The real money-saver for Virtual Server 2005, however, lies in server consolidation. For too long, Microsoft, Intel, and the systems vendors have been happy enablers of the server sprawl phenomenon that Windows shops have come to know and loathe. While the low upfront cost of "standards based" servers is a wonderful advantage over RISC and mainframe architectures, some shops have over-indulged and have come to know the insidious side effect of standards-based sprawl: inefficient use of server capacity and a higher administrative burden.

Virtual Server 2005 can allow Windows shops to reduce the number of physical servers in use. Tom Bittman, an analyst with Gartner, says that companies that don't use virtualization technologies will spend 25 percent more on their X86 servers than those that do. "Server virtualization software can help enterprises reduce the time, effort, and costs associated with the consolidation of servers and applications," Bittman says.

Microsoft says that early adopters of Virtual Server 2005 have been able to decrease their server provisioning time by 50 percent, to 95 percent, while reducing physical server counts by 50 percent, to 80 percent, through consolidation. One of Microsoft's early adopters, PING Golf, is consolidating more than three-quarters of its applications using Virtual Server. "Virtual Server 2005 will allow us to get out of the one-application, one-server paradigm when dealing with applications with low system requirements," said Eric Hart, PING's senior network engineer.

Early adopters may choose to run their critical Windows applications on top of Virtual Server, but before mainstream customers start consolidating their ERP applications onto a fewer number of bigger standards-based servers, Virtual Server will need to prove itself to be stable and secure. These, obviously, have not been Microsoft's biggest strengths, and Windows shops would be wise to ease Virtual Server into use, maybe by employing it in their testing department first. Perhaps Virtual Server is destined to reside in one of its own virtual machines for a while before being unleashed into full production.